Thanks Chris! I hope you're right. I'm now tending to agree with you, " I think these trees do have a tendency to shed branches even when healthy." This weekend, I volunteered at the Chicago Botanic Garden, and worked on a huge forest planting chamaecyparis pisifera bonsai specimen. Cutting back die back. Not a lot, but still....and it is even healthier than mine.
Luckily, (if that can be said), I'm just loosing some secondary branching right now. It really needed the repot, and I still stand by my statement, that I should've checked out the roots after buying it. But it looked healthy, enough so that I thought I could do the work on it. So for now, I've kept it in the shade, and have it on a heating mat, and another wrapped vertically as it's in this 10"D pot. Both set to 72 degrees. It's 41 outside right now and a low of 39....I feel like I've done what I can do.
And Chris, I too tend to think about loosing more trees to root rot than out of season repots, though just moving to a 'winter state'. Learned it this last year with a Chinese Elm I delayed needed repotting. So heck, I'm still learning how to deal with winter for myself, and my trees

I never had a problem repotting any time of the year in N. Cali. lol
Chris